Table 1 Hardy classification criteria for pituitary adenomas

Grade

Description of extension

Grade 1

The tumor diameter is within 10 mm and grows in the saddle

Grade 2

The tumor extends up to 10 mm to the sella and fills the suprasellar cistern

Grade 3

The tumor extends 10 ~ 20 mm to the sella, raising the third ventricle

Grade 4

The tumor extends 20 ~ 30 mm above the sella and compresses the anterior part of the third ventricle

Grade 5

The tumor extended more than 30 mm above the sella and reached the Monro foramen of the lateral ventricle with obstructive hydrocephalus

Grade

Description of invasion

A

Adenoma involving the suprasellar cistern upwards

B

Adenoma extends upwards to the base of the third ventricle, causing it to protrude upwards

C

Adenoma involving the anterior one-third of the third ventricle upwards

D

Asymmetric upward growth, with adenomas protruding into the intracranial cavity and reaching the level of the interventricular foramen

E

Asymmetric lateral growth, invading the cavernous sinus